"Starlight Honeymoon Therapy Kiss" is an extremely powerful moon-based/healing-based attack performed by Eternal Sailor Moon in the anime, manga, and musicals. It also was one of Eternal Sailor Moon's most powerful attacks.
Sailor Moon finally taps into this power when all the Super Sailor Senshi lend their strength and abilities into Super Sailor Moon's brooch, evolving her into Eternal Sailor Moon form. It was used mainly to heal a Phage and return it to their human form by using a healing command which unleashes several blasts.
When Sailor Moon used this attack in the anime, the Eternal Tiare appeared with a flash of pink light, then producing streams of rainbow-colored light from the crystal at the top of the Tiare. It began to spin fast and she appeared behind it, hands outstretched to guide the spinning Tiare above her head and then in front of herself once more. (Beginning in episode 176, there was the addition of feathers that flew across the screen as the Tiare moved above her head.) She then grabbed hold of the Tiare with her right hand and light flashed. She called out the name of the attack as she spun around, holding the Tiare above her head, and on the final word raised it high in the air with both hands. Pink light flared at the top of the Tiare and streamed toward the target in multiple waves; if the target was a Phage, a torrent of feathers would also rush past it, then the Phage cried out "Beautiful!" before returning to his or her normal state.